Rolling mill



H. SCHIMMEL ROLLING MILL Filed April 2s, 1932 2 sheets-sheet 1 INVCNTOR HANS SCHIMHEL BY ms AT1-casus Dec. 12,` 1933. H, SC'HIMMEL. 1,939,524

rROLLING MILL Filed April 2s, 1952 2 sheets-sheet 2 Fl? c? v/// u l. L fof M 'f5 77 m INVENTR HANS SCH|M MEL BY ms ATTQRNEYS MMM Patented Dec. l2, 1`933- MILING MILL Hans Schimmel, Komotau,

Application April 28, 1932.

sum No. mass,

and in Germany my 4, 1931 z claims. (ci. so-ia) mandrel. The bore of the bushing 13 is inclined This invention relates to rolling mills for the manufacture of thin walled seamless tubes from a pierced or otherwise hollowed billet.

Heretofore, seamless thin walled tubes have been rolled from pierced billets, in rolling mills having two or four inclined, barrel shaped rolls, between whichis fixed a mandrel mounted upon a mandrel shaft. When only two rolls are employed-guides are provided for stretching and rounding the tube. It has been proposed to provide hemispherical rolls, inclined if necessary, and to pass the piece ,to be worked between these rolls upon a. movable mandrel. However, this con- .struction of the rolls does not permit economical operation in practice.

Itis, therefore, an object of the invention to improve the construction and arrangement of themetal working parts of rolling mills e! this character, to permit economical operation.

In carrying out the invention, there is employe a cylindrical mandrel, freely movable in the rolling direction, together with a stretching and rounding bushing, in combination with rolls which form a reducing cone at the feeding opening, followed by a narrow transition zone and then an expanding zone.

These rolls-are preferably disk rolls arranged at an acute angle to the tube feeding opening,

' and the stretching and rounding bushing is preferably mounted for longitudinal movement with respect to the path of the tube, in order to continuously present the metal to the stretching pressure.

In the accompanying drawings- Figure 1 is a vertical section through a rollingmill according to the preferred embodiment of the present invention;

Figure .2 is a horizontal section through the same;

Figure 3 is a view modification; and

Figure 4 is a correspondingly modiiled view similar to Figure 2.

In these drawings, Figures 1 and 2 show a tube l0 which'is carried by a central cylindrical mandrel 11.v In the form shown, two or more disk rolls 12 are provide., which are mounted at an acute angle to the axis of the tube being rolled, the axes of the rolls being inclined toward the entrance end of the mill.

A stretching and rounding bushing 1 3 is interposed' between the tube 10 and the mounting of the rollers 12. This bushing is cut away to form lateral openings through which the rollers project inwardly into engagement with the tube on the similar 'to Figure 1,-showing a at the ends, resulting in a funnel-like construction.

In operation,l the mandrel 11 passes through the rolling mill, with the tube 10 thereon. The rolls 12, cooperating with the moving cylindrical mandrel, form the tube into a reducing cone, followed by a narrow transition portion, and a final expanding cone. The bushing 13, surrounding the expanding cone, causes the tube to be stretched and rounded.

In the form shown in Figures 3 and 4, the rolls 12 are also mounted at an angle to the axis of the tube 10, but in this form the axes of the rolls 12 are at anobtuse' angle to the tube-feeding opening. In these views, means are shown for advancing the bushing 13 in the direction of movement of the tube.

While electrical or mechanical means may be employed -for this purpose, nuid .pressure means, such as hydraulic cylinders v14 are shown. The cylinders 14 are mounted in the frame 15, in which the bushing 13 is slidably received.

Pistons 16 are mounted in the cylinders 14, and piston rods 17 extend therefrom, the ends of the rods being adjustably connected to a yoke 18 carried by the bushing 13. The bushing 'may be constructed in two parts.

With this arrangement, the tube 10 on the mandrel 1l is passed into the rolling mill, and the rolls 12 engage the tube, and the action' of the rolls and the moving cylindrical mandrel forms the reducing cone, narrow transition portion, and expanding cone, as described in connection with Figures 1 and 2. As the expanding cone is formed, the bushing 13 is advanced by the cylinders 14 by means of the odsY 17 and yoke 18. Thus the expanding cone engaging the bushing 13 which is advancing in the direction of Kmovement of the tube, is stretched and rounded by the action of the bushing.

The longitudinal movement `of the bushing 13 is of advantage, 'particularly in conjunction with the longitudinally moving cylindrical mandrel, in that as the expanding cone is\continuously formed, the same is continuously received by the advancing bushing, and thus a smooth and unlform operation is effected.

The tube discharged from the stretching rolling mill above described can be worked up or finished in a finishing apparatus or an expanding rolling mill followed by a reducing rolling mill.

I claim:

1. Inarollingmillformanufacturlngseamleu thinwalledtubesfrompiercedbiletsorthelihe,

roo

in combination, rolls having the axes thereof inclined with respect to the direction of movement of the piece being worked, a cylindrical mandrel movable in said direction of movement for feeding the piece to be rolled to said rolls, and a stretching and rounding bushing also movable in said direction of movement for receiving the tube formed by said rolls and continuously subjecting the same to the stretching pressure.

2. In a rolling mill for manufacturing seamless tubes, means for feeding the piece to be worked- 

